1. Field of the Invention
This invention relates to a system for detecting debris in a fluid flow and in particular to a system in which detection is achieved without disrupting the fluid flow.
2. Prior Art
A popular means of determining incipient deterioration of a mechanical system is to monitor the fluid flow serving the mechanical system, and more specifically to monitor the quantity of debris in the fluid flow. Consider, for example, U.S. Pat. Nos. 3,686,926, 3,878,103 and 4,070,660. The systems described in these patents are all located in the primary fluid flow path. See, for example, FIG. 6 of U.S. Pat. Nos. 3,686,926 and 3,878,103. In the circuit shown, the two screens and the filter are arranged in series in the oil line serving the transmission.
Any detection system which is placed in the primary fluid flow path introduces an added risk, namely, a detection system failure wholly apart from the mechanical system being served. Such a failure will disrupt the fluid flow to the mechanical system, and the consequences of such a disruption could be quite serious. For example, if in a transmission, and in particular the transmission of a helicopter, the detection system failed and lubricating fluid flow to the transmission were disrupted, the transmission could quickly seize, resulting in loss of the helicopter.